The Railway Association of Canada, whose major members include CN and CP Rail, asked the federal transport minister at the time, on June 7, 2013, to repeal rules that require certified railcar inspectors to do detailed examinations of brakes, axles, wheels and car components before they are loaded.

The RAC argued that the examinations done at designated yards were “redundant” and “overlay,” given that train conductors and engineers walk the length of their trains, and rail lines now are equipped with “wayside inspection detectors, wheel impact detectors and cold wheel set detectors.”

Last month, the RAC twice denied they had ever sought to repeal the inspection rules, until CBC News confronted the organization with its own correspondence. A spokesman released a statement Tuesday afternoon.

“The RAC proposed language to modify the rules,” wrote Paul Goyette, and among them was a suggestion to remove an inspection on dangerous goods cars before they are loaded. “In some instances, depending on route and railways involved, it might result in the elimination of a redundant inspection, but that would not have any direct impact on safety based on industry research, study and science.”

Goyette acknowledged in an earlier e-mail that “in light of events at Lac-Mégantic and in the interest of safety" the RAC withdrew its pitch to reduce inspections.

Late on July 6, 2013, an unmanned, 72-car train carrying crude oil rolled down a grade and into the town of Lac-Mégantic, Que., where it derailed and exploded, killing 47 people.

The RAC wrote to Transport Canada 12 days later, saying: “The RAC has had discussions with Transport Canada surrounding the proposed change, and at this time we both feel there is more work to be done in this area. As such, we would ask that you rescind our filing and we will revisit this matter at a future date.”

Early Wednesday, the office of Transport Minister Lisa Raitt — appointed days after the tragedy — told CBC News: "The RAC withdrew their pitch to reduce inspections and it’s a good thing they did, because I would have never allowed this to happen."

Unions warned of risk

Unions consulted on the proposed change had objected from the outset, citing safety concerns for employees and the general public.

Robert D. Smith of the Teamsters Canada Rail Conference wrote on May 21, saying that "the boom in oil production has prompted a huge rise in crude-by-rail transport as output has outgrown the existing pipeline network. Recent train derailments causing spills have heightened concerns about the environmental impact of rail shipments.”

Even though it was six weeks before the events at Lac-Mégantic, Smith wrote: “This is therefore not the time to be considering a relaxation of rules … but rather a time to maintain that which is in place to safeguard these increased movements.”

Transport Canada figures show that since 2006, the volume of dangerous goods being shipped by train in Canada has risen more than 30 per cent. However, the numbers of accidents and incidents reported by rail companies involving dangerous goods appears to be falling.

The Transportation Safety Board’s database of dangerous goods derailments and incidents reported by companies shows 3774 mishaps across the country between 2000 and 2012.

Evidence 'isn't in'

The TSB data, obtained by CBC News, suggest one-third of all problems with dangerous goods railcars was detected through inspections. Often, workers noticed the problem either by smelling it or spotting a leak.

Brian Stevens of Unifor, which represents the carmen who would normally make comprehensive inspections, echoed his May 23 objections to the proposed change, telling CBC News about the “over-reliance we see creeping into the industry where they want to rely more and more on the technology — hot box detectors, impact detectors, cold wheel detectors — to do away with the car inspections in the safety maintenance locations and say ‘listen, we have this terrific technology that’s going to tell us when cars are faulty.’

“And the evidence isn’t in on that.”

Stevens points to the recent derailment in Plaster Rock, N.B., where investigators found a broken axle contributed to the accident.

"That train had just recently passed a hot box detector and an impact detector, and didn’t note that," Stevens said. “We had a similar situation last summer in Sudbury, where there was a derailment, took out a bridge (over the Wanapitei River), and that train I believe only nine miles earlier had gone past a hot box detector that didn’t detect the failure in the wheels.”

'Dismal' success rate

“Data provided by CP in relation to Automated Train Brake Effectiveness (ATBE) scanners indicate a dismal train scan success rate of 69 per cent to date,” he wrote. “This misplaced reliance on technology thereby confirms that over 30 per cent of freight car equipment passing these detectors are not monitored.”

Last spring, the RAC argued that it had done a risk assessment and noted that the combination of inspections — by conductors and locomotive engineers who “have been extensively trained” to spot problems, and the automated detectors — would help prevent derailments.

Transport Canada refused to tell CBC News how many of their own inspectors are dedicated to inspections of dangerous goods cars, and whether those inspectors are on the ground or simply monitoring rail company reports on self-inspection.

In an email to the CBC, Transport Canada said: "Railway companies are responsible for the safety of their rail line infrastructure, railway equipment and operations. This includes ongoing inspection, testing and maintenance programs in accordance with regulatory requirements, as well as any particular operating and environmental conditions."

Transport Canada did not respond to questions about its discussions with the RAC to reduce the inspections.